Darius’ departure seems to indicate clearly that he had for the time being given up all idea of the immediate prosecution of large designs in the West.
There are several reasons which may be suggested for the temporary abandonment of his plans.
There can, in the first place, be little doubt that the campaign in Thrace had not ended in anything resembling the complete subjugation of that difficult country. Disaster in the Scythian expedition had seriously shaken Persian prestige, not merely on the European, but also on the Asiatic side of the Propontis; and though Megabazos’ campaign may have staved off actual danger, its positive results appear to have been but partial, and not such as to warrant further advance.
By the time that campaign came to an end Darius must have been absent from Susa for a space of well-nigh two years; and so prolonged an absence in one remote corner of the empire, far away from the real centre of government, must have had its inconveniences, if not its dangers, in a dominion so wide and so recently reduced to obedience.
The postponement of success in Thrace was the first cause of the postponement of the designs on Greece.
During the years between the departure of Darius from Sardes and the occurrence of those incidents which led to the outbreak of the Ionian revolt Persian history is almost a blank. Darius, the central figure of the whole drama, vanishes from the stage for a long interval of years. Had he, like the Nebuchadnezzar of the Book of Daniel, been driven forth among the beasts of the field, his effacement from written record could hardly have been more complete. H. ii. 110. There is an incidental tale in Herodotus’ Egyptian history which refers to a visit of Darius to Egypt, made possibly during this time. If the tale be true, the incident certainly occurred after the Scythian expedition; and the campaign in Cyrene, or the settlement of affairs after it, may have called for his presence in that part of the empire.
Otherwise, in so far as is known, he spent these years at Susa, where he appears to have been at the time of the outbreak of the Ionian revolt.
Otanes, Megabazos’ successor, is engaged in a campaign against the revolted Greek cities of the Hellespontine region, which are once more brought into subjection; but there is no means of judging how long the campaign lasted.
Did he carry on the operations in Thrace? Probable though the conjecture may be, there is no evidence that he did so, H. v. 116. save the very indecisive fact that he is still in Asia Minor at the time of the revolt.
Artaphernes is satrap at Sardes throughout the interval, and during his tenure of office there is a distinct and striking development of the relations between Persia and European Greece. It is remarkable that it is from the side of Greece,—from Athens, above all,—that the first advances are made.